1. Field of the invention
This invention relates to the production of a filler material for dyestuff compositions. More particularly, this invention relates to a process for treating kraft black liquor to remove a substantial amount of the lignin portion and to stabilize the material against fiber staining and dye reduction to thus make it suitable as a filler material in dyestuff compositions.
2. The Prior Art
Dyestuff compositions, for the most part, the dye cake, i.e., a dispersed dye or a vat dye, a dispersant, and a "filler" or, as it is sometimes called, a diluent. Fillers are basically ingredients to dilute a milled dyestuff composition to a certain color value or dye strength which is accepted by the industry as a standard and which do not interfere with the dispersion phenomona of the product in use. The filler, in addition to being inexpensive, may assist the dispersant by serving as a humectant and providing redispersibility. The filler should also be low in foaming, low in fiber staining, and should not be detrimental to the heat stability of the dispersed dyestuffs. In addition, it is desirable that the fillers do not form thixotropic mixtures or contribute to the overall viscosity. When used with azo-type dyes, the filler must also not have a tendency to reduce the diazo dye linkage. The disperse and vat dyestuff compositions are widely used to color both natural and synthetic fibers; and when used with fillers, the fillers may be added to a dye bath.
As stated, because in many instances large amounts of filler are used, it is essential that the filler, in addition to having the desired properties, be relatively inexpensive. Thus, attempts in the prior art have been made to provide fillers from numerous sources. One of the sources which has been investigated for obtaining dyestuff fillers is a product obtained from the spent liquor resulting from the sulfite pulping of wood as disclosed in U.S. Pat. No. 3,156,520 to Blaisdell. However, as will be shown hereinafter, the products of the claimed invention as modified exhibit certain advantages over those disclosed in Blaisdell.
It is thus the general object of this invention to provide a filler material from kraft black liquor for use with dyestuff compositions.
Another object of this invention is to provide a filler material obtained from the filtrate of kraft black liquor.
An even further object of this invention is to provide a process for treating kraft black liquor to render it suitable for use as a filler for dyestuff compositions.
Yet another object of this invention is to provide a filler material for use with disperse dyes or vat dyes having humectant properties.
Still another object of this invention is to provide a filler material from kraft black liquor which has been sulfonated and air oxidized to provide a stable dyestuff composition filler.
Other objects, features and advantages of this invention will be evident from the foregoing detailed description.